I've heard a lot of people opine that they like the older-style S&W revolvers with the firing pin mounted on the hammer. Until recently, I didn't even know such a thing existed. But now I"m curious: Why is the firing pin on the hammer to be preferred? Doesn't it cause the same problem that old single-action revolvers had, where if the hammer was down on a live round a blow to the hammer could fire the round?